Pneumatic tire

Active Publication Date: 2005-05-19
SUMITOMO RUBBER IND LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0013] A tire is disassembled and a carcass cord removed from the disassembled tire is used as the test material. When the intermediate elongation Es is measured, a portion of the carcass cord located at the maximum width position is located at the center between grasping sections of a tensile testing machine. Similarly, when the intermediate elongation Eb is measured, a portion of the carcass cord located at the height position of the radially outermost end is located at the center between grasping sections of a tensile testing machine. Since a large number of carcass cords exist in the tire circumferential direction, in this specification, one carcass cord is selected from equal four locations on the circumference of the tire, the intermediate elongation of each of the selected carcass cord is obtained, and average value thereof is used. Rubbers adhered to peripheries of the carcass cords are carefully removed and then the test is carried out.

Problems solved by technology

Such a method is effective for enhancing the steering stability, but since a vertical rigidity of the tire is also increased, the riding comfort is deteriorated.
In recent years, it has been found from various experiments that if the height of the bead apex rubber is increased to increase the vertical rigidity, road noise performance (noise inside the vehicle) is deteriorated, and especially the noise performance in a low frequency band of about 100 to 160 Hz is deteriorated.

Method used

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Examples

Experimental program
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Effect test

embodiments

[0040] Passenger vehicle radial tires having size of 195 / 65R15 were prototyped based on the specifications shown in FIG. 1 and Table 1, and the following basic performance was measured and evaluated. The carcass comprises one carcass ply having polyester cord of 1670 dtex / 2, and tensions of parts of the tire were made different at the time of vulcanization, thereby adjusting the intermediate elongations Es and Eb.

[0041]FIG. 3 shows distribution of the intermediate elongation E from the position F of the outer end of the belt layer to the position B of the bead portion of a tire of each of typical embodiments 1 to 4 and comparative examples 1 to 2. FIG. 4 shows values of the intermediate elongations Es and Eb at the positions M and B of the tire.

[0042] The test method is as follows:

[0043] Prototyped tires were mounted on four wheels of a vehicle (FF vehicle having displacement of 2500 cc) under conditions of rim (15×6JJ) and internal pressure (210 kPa). Only one person was in the ...

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Abstract

A pneumatic tire, comprising a carcass having a carcass ply_(6a) with a folded part (6b) folded up around a bead core (5) from the axial inside to the axial outside of the tire continuously fitted to a ply body part (6a) installed across the bead cores (5) and (5), wherein the intermediate elongation (Es) of a carcass cord in the ply body part (6a) at the maximum width position (M) is smaller than the intermediate elongation (Eb) thereof at the height position (B) of the bead core at the radial outermost end of the tire.

Description

TECHNICAL FIELD [0001] The present invention relates to a pneumatic tire capable of enhancing, in excellent balance, basic performance of a tire such as steering stability, riding comfort, noise performance. BACKGROUND TECHNIQUE [0002] In order to enhance the steering stability of a pneumatic tire, it is effective to enhance a flexural rigidity of a sidewall portion. For this purpose, a high modulus carcass cord is used to form a bone of the tire, or a bead apex rubber disposed in the bead portion and having a triangular cross section is increased in size. [0003] Such a method is effective for enhancing the steering stability, but since a vertical rigidity of the tire is also increased, the riding comfort is deteriorated. In recent years, it has been found from various experiments that if the height of the bead apex rubber is increased to increase the vertical rigidity, road noise performance (noise inside the vehicle) is deteriorated, and especially the noise performance in a low f...

Claims

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Application Information

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IPC IPC(8): B60C9/02B60C13/00B60C15/06
CPCB60C9/02B60C13/00Y10T152/10837Y10T152/10819Y10T152/10873B60C15/06B60C2013/007
InventorYAMAMOTO, EMIKO
OwnerSUMITOMO RUBBER IND LTD